In a network system such as Internet Protocol TV (IPTV), a digital television service is delivered over a network structure, using the Internet Protocol. The IPTV content may be delivered by a high-speed data transmission rate internet connection (broadband connection), such as Digital Subscriber Line (DSL) or cable modem. As IPTV evolves, the underlying network architecture provides for delivery of content to multiple devices. These devices may vary between low-powered cell phones; medium-powered handheld game consoles, high-end workstations, and set top boxes. The access networks can also vary with fluctuating bandwidth.
In current implementations of IPTV content delivery, when delivering for multiple devices, the signal from the source may be fed into an encoder to compress the data in order to shrink the required bandwidth burden on the network. In the currently used encoders, an output signal may be generated at a particular bit rate demanded by targeted devices.
When multiple devices with varying capabilities (e.g. cell phones, Standard Definition (SD) television, High Definition (HD) television) are to receive the content, then multiple encoders may be needed to feed the exact same piece of data from the same data source and generate outputs at different bit rates, as required by the targeted receiving devices. The generated multiple data rate outputs have to be carried over transport networks to their final destinations. For example, an HD video source may be used to generate data for four separate devices with bandwidth of 0.3, 2.5, 4, and 9 megabits per second (Mbps). This would require four separate encoders to generate four separate streams transported over the IP infrastructure and then to be delivered to the individual devices. The aggregate bandwidth for the entire data in this case amounts to 15.8 Mbps (9+4+2.5+0.3), which dictates the bandwidth required by the IP infrastructure for delivering the video content to the targeted devices.